Each of the VHS and Betamax videotape cassettes has one tape roller and three steel guide posts. Current standards for these cassettes require the tape roller to consist of a fixed steel pin and a rotatable plastic sleeve. Because of clearance between the ends of the sleeve and the cassette walls, the sleeve may strike the walls repeatedly to produce a chatter which is audibly objectionable to some users. Audible noise also is generated due to the clearance between the steel pin and its sleeve. The fixed steel posts scratch the tape, create a substantial frictional drag on the tape, and if they were replaced by rollers, much less torque would be required to drive the tape.
In order to reduce driving torque, the VHS-C (compact) videotape cassette has no posts and instead has five tape rollers, each consisting of a steel pin and a plastic sleeve. The cummulative chatter of these five tape rollers has been annoying to many users. If assembly of the compact VHS-C cassette were to be automated, it would be desirable to insert the five steel pins simultaneously, but this would be impossible since each pin should fit into zero-clearance openings in the cassette walls.
Many audiotape cassettes have no tape rollers and instead employ plastic posts which are projections from the cassette walls. Friction between the tape and posts produces debris which can contaminate the surfaces of the recording head and tape. In more expensive, higher quality cassettes, the posts are replaced by tape rollers similar to those of the VHS cassettes, with similar noise and assembly problems.